Objective  To summarize the clinical features and treatments of autoimmune encephalitis (AE) patients with mental disorders as initial symptoms.

  Methods  The clinical manifestations, auxiliary examinations and treatments of 28 AE patients with mental disorder as initial symptoms were analyzed retrospectively.

  Results  Among the 28 patients, 25 cases were encephalitis with positive immunoglobulin G (IgG) of anti-glutamate receptor (NMDAR) antibody, of whom 5 cases were complicated with ovarian cyst or teratoma. Two cases were encephalitis with positive IgG of anti contactin-associated protein receptor 2 (CASPR2) antibody. One case was encephalitis with positive IgG of gamma aminobutyric acid type B receptor (GABABR) antibody. With the progress of the disease, 17 patients had seizures, and 14 patients had different degrees of disturbance of consciousness. Most patients had abnormal electroencephalogram. Finally, 26 patients were treated with first-line immunotherapy, 25 patients had good effect, and one patient had no effect.

  Conclusion  For patients with mental disorders as initial symptoms, if they have epilepsy, disturbance of consciousness and other symptoms, AE should be highly suspected, and the head magnetic resonance imaging (MRI), electroencephalogram, cerebrospinal fluid examination and other related examinations should be performed as soon as possible. If AE is diagnosed, immunotherapy and other symptomatic treatments should be given as soon as possible to improve the prognosis of patients.